1. Field of the Invention
This invention relates to handles for surgical instruments. In particular, this invention relates to an improved handle for hand held surgical instruments of the type having a tool with at least one articulated member thereon wherein the handle has a means for actuating the articulated member.
2. Background Art
Surgery is a learned art requiring many hours of advanced training and skills development that extends far beyond a thorough understanding of the medical principals involved, e.g., anatomy, physiology, principals of wound healing, and the like. The surgeon must also develop hand to eye coordination and acquire skills in the art of atraumatic tissue manipulation utilizing a variety of highly specialized surgical instruments.
The surgical instrument actually becomes an "extension" of the surgeon's hand. The surgeon must develop an ability to "feel" and respond, often delicately yet firmly, through his surgical instruments. Accordingly, there exists a need for instrument handles which are sensitive, responsive and ergonomically designed to augment the natural motions of the human hand.
The apposition between thumb and the index finger is the most sensitive and most often used means for delicate touching or for picking up small objects in every day affairs. Prior to the present invention, however, there were no surgical instrument handles designed to fully utilize the sensitive and delicate opposition capabilities of the thumb and index finger for movement of the lever arm of an instrument handle.
The actuating mechanism for handles of currently available surgical instruments are usually configured such that the pivot point is located between the handle lever and the articulated member (a forwardly located pivot point). The handle can have either one or two lever arms which are moveable about the pivot point. Such configuration is opposite to the natural pivot points of the hand.
One example of prior art handles of the type described above is the conventional "scissors-type" handle with a forward pivot point, e.g., Mayo or Metzenbaum scissors, or Debakey forceps. The scissors-type handle design usually lacks a means for biasing the instrument tool in an open position. Of necessity, therefore, these scissors-type handles have finger and thumb rings located at the free ends of the lever arms which provide a means for receiving force and balancing the instrument when both opening and closing the lever arms of the handle.
The scissors-type handles are usually held by inserting the thumb through the thumb ring, balancing the scissors against the index finger and inserting one or more of the remaining digits into the finger ring of the opposite lever. Movement of the lever arms is accomplished by apposing the thumb and digits which are in the finger ring. This design requires increased muscular effort to open and close the levers and therefore fatigues the hand of the surgeon.
A second example of the forward pivot point configuration is the "pliers-type" handle which is functionally similar to the scissors-type handle but without finger rings. In this configuration, movement of the levers from the open to the closed position is accomplished by closing the palm of the hand in a squeezing motion. A bow spring or other spring configuration located between the lever arms is sometimes included as a means to bias the handle in an open position to compensate for the lack of finger rings.
Neither the scissors-type nor the pliers-type handles are capable of being held and moved by the tips of the fingers, which results in a significant loss in sensitivity.
A third type of handle utilizes an actuator having two bowed springs connecting a rearwardly projecting actuator rod to handle levers which pivot about a forward pivot point. Although this handle may be held in a manner which allows for fingertip control, the forwardly located pivot point, opposite from the natural pivot point of the hand, results in loss of leverage and decreased sensitivity of the instrument. For fingertip control, the surgeon must sacrifice leverage by placing the fingertips away from the lever ends and closer to the forward pivot point.
One type of instrument which utilizes a rearwardly located pivot point is the forcep e.g., Adison, Potts-Smith, or general tissue forcep. Forceps utilize the thumb and index finger in a "pencil" grip fashion. However, forceps are not designed to activate an articulated member of a tool e.g., a needle holder, retractor, or hemostat. Rather the distal ends of the forcep lever arms actually comprise the tool itself.
Accordingly, there is a need in the art for a more sensitive and ergonomic instrument handle which is designed to functionally mimic and create functional harmony with the natural gripping mechanism and motion which exists between the thumb and index finger of the human hand. There is also a need in the art for a surgical instrument handle which is simpler to manufacture, assemble and disassemble than the prior art.